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Virtual processor tech heads for Linux mobile phones

Dec 12, 2005 — by LinuxDevices Staff — from the LinuxDevices Archive — 4 views

Jaluna has revised its virtual platform software aimed at letting reference design vendors and device makers add Linux to designs for inexpensive mobile phones. OSware for ARM 2.0 lets Linux and legacy RTOSes (real-time-OSes) share a single processor, and has been adopted by Philips for a single-chipset mobile phone reference design expected next year, Jaluna says.

Jaluna first offered OSware in May of 2004, saying the technology could bring the power of virtualization to embedded systems. A version for Texas Instruments (TI) DSPs subsequently found a niche in the set-top box market, Jaluna says, with Amino and others using it in inexpensive, high volume devices.

OSware for ARM, however, in its first two years of development remained “more a technology than a product,” admits Jaluna Co-Founder Michel Gien. Now, thanks to “interactions with customers over the past few months,” Gien says Jaluna has simplified the process of adapting OSware to specific boards, as well as simplifying the support of Linux. “We now have a product,” Gien said. “It is able to cope with all the complex features that need to be handled when you start to put together two OSes. There is a mechanism for sharing resources between the RTOS and Linux instances, a fine-grained scheduler, power management — everything needed to build a real product.”

What is OSware?

OSware comprises a small nanokernel that divvies up hardware resources such as physical memory between guest OSes. The nanokernel also virtualizes and schedules processes, respecting real-time requirements. OSware additionally includes a virtual bus for inter-OS communications, operated by a bus driver running under each OS.


OSware allows multiple OS instances to co-habitate a single processor

Supporting Linux alongside a legacy RTOS under OSware requires a port of OSware to the particular architecture, along with adaptations to both guest OSes, particularly at the driver layer. OSware customers can make the required changes themselves, or hire Jaluna. “Customers often find it faster to hire us,” Gien says.

Once the needed ports, drivers, and OS elements are in place, the two OSes run as if they were running on separate processors, Gien says. “The application environment is mixed, with some applications being run on the RTOS, and some on Linux, synchronized as if they were running on two processors.”

Philips mobile phone reference design

Jaluna says Philips will use OSware in a mobile phone reference design targeting inexpensive, high-volume 2.5 and 3G products. Gien said, “We are announcing a relationship. Philips has made this selection, and licensed software for use in this project. We hope there'll be product announcements from them shortly. It's a validation of our claim that [OSware] would be useful in phones.”

According to Gien, the Philips design will be powered by a single RISC/DSP chipset that will support the Philips wireless stack, an RTOS managing telephony functions and applications, and an embedded Linux OS running higher-level applications. The chipset will have an ARM926-powered applications processor, along with an unspecified DSP co-processor.

Gien declined to state which specific processor the Philips design will use, but given Jaluna's previous work with DSPs from Texas Instruments, one possibility appears to be TI's ARM926TEJ-based Vox, which the mobile chip marketshare leader specifically markets as a Linux-friendly standalone single-chip mobile phone platform, and which was introduced earlier this year.

Single-chipset designs represent a hardware simplification breakthrough over currently available Linux phones, although MontaVista and others say they are working toward the same goal. Single-chipset designs promise to reduce bill-of-materials costs and hardware design complexity, resulting in smaller, less expensive phones that consume less power. This, in turn, could allow wireless cellular technology to pervade new classes of devices, such as portable multimedia and gaming gadgets.

Enabling inexpensive, featurephone-level hardware to run Linux holds the promise of allowing integrators to leverage readily available, quickly evolving open source applications for Web browsing, e-mail, calendaring and high-end multimedia applications. This could ultimately bring smartphone-like features to featurephone-level phone hardware.

Brian Meads, smartphone marketing manager at Philips, said, “Philips has recognized the tremendous opportunity that Linux brings to the mobile market. Jaluna OSware enhances Linux with a compelling and cost-efficient new approach.”

Philips may already be using Linux in some of its mobile phones; its CT9688 (pictured at right) may be based on a Linux/Qtopia design created by Cellon International, a mobile phone ODM (original design manufacturer) that spun off from Philips.

Analysis

Most companies and organizations bent on bringing Linux to consumer devices attempt to re-engineer Linux to take the place of legacy RTOSes. Such efforts include CELF's Linux tree, MontaVista's Open Source Real-Time Linux project, and most recently, the OSDL's Mobile Linux Initiative.

Jaluna appears to be taking the fundamentally different approach of making it possible to simply add Linux — with all the richness of open source applications that that implies — while preserving legacy RTOSes and applications. This bottom-up approach calls to mind the unique French word bricolage, which has no English equivalent, but suggests a resourceful, clever way of fixing or building things from scratch using pre-existing components. Examples of bricolage might include a meal deftly assembled from leftovers, or perhaps fixing a broken-down Peugeot using materials salvaged from roadside debris.

If this sounds like a put-down, it's not; bricoleurs, or “tinkerers,” enjoy high status in French culture, as readers of Jacques Derrida's analysis of Claude Levi-Strauss may already be aware. Indeed, bricolage has a similar connotation to that of hacking itself, in which the goal is to solve problems in the simplest, most elegant way, with the least effort expended. Why write a C++ application if a bash script will do?

Jaluna says its product can preserve “legacy” OS and application investments, and minimize re-engineering efforts. This, in turn, reduces staff re-training and tool obsolescence. Another claimed benefit is that the technology can provide a transitionary step in a migration path toward full Linux.

On the downside, implementing the technology currently appears to require multiple low-level OS modifications and driver implementations that are likely beyond the reach of most product designers. At the moment, the ability to create or fund these ports rests with a fairly select group of semiconductor vendors, ODMs/OEMs (original design/equipment manufacturers), and reference design vendors.

To overcome this situation, however, Jaluna is in the process of creating tools to simplify the adaptation of its embedded virtualization platform to additional hardware and RTOS environments, according to Gien. Also, the company offers porting services to its customers, Gien notes.

Potential customers

Who are OSware's potential customers? Gien answers, “This is one product from Philips — there may be others from them. There are others doing reference designs for phones. TI, Freescale, NEC, Panasonic, Qualcomm — a dozen companies [that are potential customers]. Then there are phone manufacturers doing integration themselves, like Nokia and Ericsson, and Qualcomm. Then there are Chinese and Korean companies that sometimes buy chipsets and do their own wireless stacks. There are a wide number [of potential customers].”

And how many potential customers are actual customers? Gien replies, “It's not just Philips. We have a number of industry customers. Semiconductor vendors, OEMs — Philips is just the first one [on ARM] that we can really talk about.”

If Jaluna wins enough customers to help create or fund timely, productized versions of its technology for specific architectures and common legacy RTOSes such as VxWorks, OSware could proliferate very quickly, especially if these products reach market in advance of more top-down Linux re-engineering efforts being undertaken elsewhere.

Gien concludes, “Now that we have a standard product on ARM, customers can insert OSware on many different devices that are ARM-based.”


 
This article was originally published on LinuxDevices.com and has been donated to the open source community by QuinStreet Inc. Please visit LinuxToday.com for up-to-date news and articles about Linux and open source.



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